Gm Global Technolgoy Operations, Inc.

Kenneth R Cross

David L Clingman

John R Cavanagh

Berton Schechter

Lawrence E Brown

Michael J Barber

Bruce A Ewing

John F Kroemer

An abrasive system and a processing procedure is provided which permits the direct installation of a thick abrasive blade tip cap onto a cast turbine rotor blade during a heating schedule which requires two furnace operations. The composition of the abrasive blade tip cap advantageously utilizes the high temperature performance capabilities of equiaxed or single crystal rotor blade alloys without significantly affecting their mechanical properties as a consequence of the processing necessary to permanently bond the abrasive blade tip cap to the rotor blade. A semi-rigid mat consisting of the preferred abrasive composition is first consolidated in a first vacuum furnace operation. Blade tip cap preforms are then cut from the mat and positioned on the tip of the rotor blade. The preform and rotor blade are then heated in a vacuum furnace according to a temperature schedule entailing heating rates, holding temperatures and durations which are sufficient to bond the preform to the rotor blade. The rotor blade is then rapidly cooled in the vacuum furnace to retain the microstructure and mechanical properties of the rotor blade.

Method for bonding abrasive blade tips to the tip of a gas turbine blade

An abrasive system and a processing procedure is provided which permits the direct installation of a thick abrasive blade tip cap onto a cast single crystal turbine rotor blade during a single heating schedule requiring only one furnace operation. The composition of the abrasive blade tip cap advantageously utilizes the high temperature performance capabilities of the single crystal alloy without significantly affecting its mechanical properties as a consequence of the processing necessary to permanently bond the abrasive blade tip cap to the rotor blade. A semi-rigid blade tip cap preform is first formed and positioned on the tip of the rotor blade. The preform and rotor blade are then heated in a vacuum furnace according to a temperature schedule entailing heating rates, holding temperatures and durations which are sufficient to bond and consolidate the preform. The rotor blade is then rapidly cooled in the vacuum furnace to retain the single crystal structure of the rotor blade.

Abrasive blade tips for cast single crystal gas turbine blades

An improved method for coating a porous metal laminated structure having air flow holes on the coated side of the structure including in part, the steps of roughening an exposed surface of the porous laminated material and thereafter spraying a bond layer on the roughened surface at an angle selected to coat it with a thin bond coat layer while depositing only a limited amount of the bond coat material internally of the air flow holes and thereafter spray coating the bond coated surface with a top ceramic coat of heat resistant composition and characterized by requiring a bond coat for adherence to the porous metal laminated material and wherein the top ceramic coat spray angle is inclined opposite to that of the spray angle of deposition of the bond coat material to prevent deposition of the top coat on bond material internally of the air flow holes so as to prevent bonding of the ceramic top coat in the air flow holes thereby to minimize restriction of flow through the air flow hole in the exposed surface of the porous metal laminate.

Method for coating porous metal structure

An abradable ceramic seal coating on at least one of a pair of members having relative rotational movement, the coating being formed of stabilized zirconia which is codeposited with a thermally decomposable organic powder, the codeposited layer being heated to decompose the organic filler and produce a porous coating of from about 20 to about 33% voids.

Abradable ceramic seal and method of making same

A method of fabricating a hybrid dual property wheel assembly includes the steps of preforming a bladed ring of a highly solidified alloy material including a base with a large diameter central opening therethrough and thereafter supporting a metal disc therein to form front and rear joint lines on either side of the juncture between the bladed ring and the disc. The method further contemplates direction of radio frequency energy to the disc to cause it to thermally expand into radially pressed contact with the inside diameter of the bladed ring at an interface therebetween while maintaining the disc and bladed ring under a continuous vacuum atmosphere and heated by the radio frequency energy for maintenance of a diffusion bond temperature between the expanded disc and the surrounding bladed ring of the wheel assembly to form a metallurgical connection therebetween by metal growth across the interface.

Turbine rotor fabrication by thermal methods

A method for manufacturing a hybrid, dual property turbine wheel assembly comprising the steps of preforming a blade element and separate support ring of a supperalloy material and locating the blades in support slots in the outer diameter of the support ring and radially outwardly of a preformed inner diameter underlying base tangs on each blade element; vacuum braze sealing each of the base tangs within a support slot and thereafter machining the inside diameter of the ring to expose the base tangs; thereafter joining the ring and undercut base tangs thereon to the outside diameter of a preformed disc element and vacuum braze sealing the hub disc and ring blade assemblies to produce a sealed interface region between the outside diameter of the hub element and the inside diameter of the ring and base tangs; and thereafter directly hot isostatically pressing the joined parts to form a direct diffusion bond between the tangs, ring and disc.

Growing community of inventors

Lebanon, IN, United States of America

Kenneth R Cross